Pressure-alarm for gas-supply pipes to furnaces



(No Model.)

I F. s. BAKER. PRESSURE ALARM FOR GAS SUPPLY. PIPES T0 FURNACES.

Pgtentfiedrgeb. 4, 1896.

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NITED STATES Prion.

ATENT FRANCIS S. BAKER, OF CHICAGO, ILLINOIS.

SPECIFICATION forming part of Letters Patent No. 554,016, dated February 4;, 1896.

Application filed July 22, 1895. Serial No. 556,704. (No model.)

To all whom it may concern:

Be it known that I, FRANCIS S. BAKER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Pressure-Alarms for Gas-Supply Pipes to Furnaces, &c., of which the following is a specification.

My invention relates to apparatus for preventing danger of explosions or injury from abnormal variations in pressure of natural gas or other fluids supplied to houses and other buildings, and more particularly to improvements upon the apparatus for this purpose shown and described in my pending application, Serial No. 535,229, filed January 17, 1895.

The object of my present invention is to provide means not only for automatically operating a bell or other alarm, but also to shut off the supply of gas to the furnace orburner in case of abnormal or dangerous variations in pressure; to provide, further, means for preventing sudden movement or jumping of the mercury in the bent tube and unnecessary setting off the alarm by sudden pulsations or fluctuations in the gas-pressure of a momentary character, and to generally perfect and improve the construction of the apparatus shown and described in my said pending application.

To render the gas-pressure steady upon the mercury in the bent tube and prevent sudden movements of the mercury and unnecessary closing of the electric circuit controlling the alarm device, I combine with the other parts of the apparatus a reservoir or vessel inserted in the gas-pipe leading to the mercury-containing bent tube and make its inlet and outlet openings comparatively small apertures, so that any variation of pressure in the gassupply pipe will not be instantly and suddenly communicated to the mercury in the bent tube, while at the same time it may be communicated gradually thereto. By this means I effectually obviate all trouble due to sudden and momentary fluctuations or pulsations in the gas-pressure in the supplypipe and prevent the giving of unnecessary alarms.

To close off the supply of to the furnace, stove or other burner, I combine with the other parts of the apparatus a valve in the gas-supply pipes anda motor operated or controlled by the electric circuit for turning or operating the valve. By this improvement I am enabled by my apparatus not only to antomatically give an alarm in case of abnormal or dangerous variation in pressure but also to automatically shut off the supply of gas to the furnace or burner,.and thus prevent all danger in cases where the house or building should have no one in it or within hearing at the time when the alarm is given.

In the accompanying drawings, forming a part of this specification, Figure l is a diagram view of an apparatus embodying my invention. Fig. 2 is an enlarged front elevation showing the box or case containing the mercury-controllin g bent tube, annunciator-drop', and other parts. Fig. 3 is a detail sectional View of the reservoir or vessel for equalizing the gas or fluid pressure against the mercury in the bent tube. Fig.4 is a detail view showing the motor or mechanism for operating the valve in the supply-pipe leading to the furnace or burner, and Figs. 5 and 6 are detail views of circuit-closers used in connection with the valve-operating motor.

In the drawings, A represents a natural gas or other fluid supply pipe; B, a furnace, stove, or burner where the gas is used for fuel or other purposes. 0 is an electric battery or other source of electric energy; D, a bent tube, inverted siphon, or two-limbed vessel containing mercury or other conducting-liquid d; E, an electric bell or alarm; F, the electric circuit having terminals ff f f in the bent tube between which the circuit may be closed by the rise or fall of the mercury therein, and G is the annunciator-drop.

All these parts are, or may be, constructed and arranged substantially as'shown and described in my said pending application.

The inverted siphon or bent tube D is connected by a coupling or union D with a branch pipe a communicating with the gassupply pipe A. Inserted in this branch pipe a between the bent tube D and the supplypipe A is the pressure regulating or equalizing vessel II, the same being furnished with a small or contracted inlet opening or aperture h and a similar outlet opening or aperture h, so that the gas can only flow into or out of this vessel gradually or slowly. The i inlet and outlet apertures ii and h are preferably each formed in a disk il of elastic or 1 packing material +1 preferably lead) inserted in the pipe (I and clamped by the coupling sleeve or nut iv.

The bent tube or two-limbed vessel 13 has i a cap (Z' covering its free leg or limb, which is provided with a small opening or aperture (P, so that the atmospheric pressure may act upon the mercury d in the bent tube. This small opening or aperture (i in connection with the air-space above the mercury in the up er end of the tube operates also somewhat in the nature of an air-cushion to prevent sudden movements of the mercury due to momentary fluctuations of pressure in the gassupply pipe; and it cooperates with the pressure equalizing or regulating reservoir f H in preventing unnecessary closing of the electric circuit by sudden and momentary fluctuations of pressure.

K is a valve in the gas-supply pipe A leading to the furnace. and M isa motor actuated or controlled by the electric circuit for automatically closing the valve K and thus shutting oil the supply of gas to the furnace when the circuit F is closed by the mercury d in the bent tube D atff or at f f Thismotor l\.[ may be of any suitable form or construction known to those skilled in the art, and which is adapted to be operated or to be released or set in operation by the closing of the electric circuit F.

In practice I have found it convenient to employ a simple but old and familiar form of electric motor for moving the valve K, and the same consists essentially of an electromagnet 121, included in the circuit F, a vibratv ing spring-retracted armature n), normally included in the circuit F and operating to break the circuitmomentarily when attracted by the magnet m. it i s furnished with a pawl or arm m engaging a ratchet or toothed wheel m on a shaft m which is provided with a crank 7715, connected by a link m" with l the valve-stem K of the valve K. A halfturn of the shaft in operates to close the valve K, and the shaft is provided with a contact wheel or disk m included in the circuit F by contact-pieces m m the wheel or disk m having a notch m to break the circuit through the magnet m as soon as the shaft on has been given a half-turn and the valve K closed. The shaft m is also furnished with a wheel or disk on of insulating material furnished with a contact-piece 777/ included in the circuit F, and which in connection with the contact-piece in closes the circuit F around the magnet on the moment said circuit is broken at m m as before described, thus short-circuiting the magnet m and keeping the circuit F closed through the alarm-bell E, so that the alarm will continue to ring after the gas has been shut off at the valve K.

The annunciator-drop G has a magnet g normally included in the circuit F when the same is closed by the mercury (Z at ff or at f f so that the continued ringing of the alarm or the continued operation of the mechanism for closing the valve K in the supplypipe is not dependent upon the keeping of a the circuit F closed at f f or f f through the mercury 11.

The annunciator-drop lever g is held normally elevated or retracted by a pawl g on the armature-lever g \Vhen the annunciator-drop lever 11 is released by movement of the armature it closes the circuit F through the contact-piece g, the frame g, and thence through the circuit-wire to the switch N, thus short-circuiting the magnet g and also the mercury (Z in the bent tube and the circuitwires leading thereto.

Beginning at the battery the circuit F may be traced as follows: first through wire F to binding-post F wire F to terminals f f" or f f and mercury (Z, wire F", magnet g, wire F spring F. drop-lever 9, frame g, wire F, switch N, wire F binding-post F wire F", binding-post F wire F magnet in, armature in", wheel m shaft m contact-wheel m contactpiece T129, wire F binding-post F, wire F alarm E, wire F back to battery. W hen the annunciatordrop lever y is released, the circuit extends directly from the binding-post I through the branch or shortcircuit wire F to the contact-piece 9', thus cutting out the magnet g and the mercury (Z.

lVhen the valve K is closed and the circuit broken at the notch m and contact-piece m, the circuit extends directly from the bindingpost F and contact-pieces m m and wire F and binding-post F and wire F to the alarm E, thus shortcircuiting or cutting out the magnet in.

The terminals ff in one leg or limb of the bent tube or vessel B are at a different level from the terminals f f in the other leg or limb of the vessel, so that the circuit F may be closed either by an abnormal or dangerous rise or by an abnormal or dangerous fall of pressure in the gas-supply pipe.

The switch N enables the circuit F to be broken by the attendant, so that he can stop the further ringing of the alarm-bell after his attention has been called to the apparatus. It is also necessary when for any cause the gas is shut off designedly-as, for example, when the furnace is not being used or when the apparatus is being put up.

The branch pipe a, leading from the supply-pipe A to the bent tube or vessel D, is furnished with a shut-off cook or valve a to enable the gas to be shut off from the vessel 1) and the parts connected therewith when desired.

I claim-- 1. The combination with a furnace or gasburning device and its supply-pipe of an elec tric circuit, an alarm device included in the circuit, a bent tube containing mercury communicating at one end with the gas-supply pipe, electric terminals or contact-pieces con- IIO nected with said circuit and between which the circuit is closed by the mercury in said bent tube when acted upon by a change of pressure in the gas-supply pipe, and a pressure regulating or equalizing reservoir or vessel inserted between said gas-supply pipe and said bent tube, substantially as specified.

2. The combination with a furnace or gasburning device and its supply-pipe, of an electric circuit, an alarm device included in the circuit, a bent tube containing mercury communicating at one end with the gas-supply pipe, electric terminals or contact-pieces connected with said circuit and between which the circuit is closed by the mercury in said bent tube when acted upon by a change of pressure in the gas-supply pipe, and a pressure regulating or equalizing reservoir or vessel inserted between said gas-supply pipe and said bent tube, said reservoir or vessel having small or contracted inlet and outlet openings or apertures, substantially as specified.

3. The combination with a furnace or gas burning device and its gas-supply pipe of an electric circuit, a bent tube containing mercury communicating at one end with the gas supply pipe, electric terminals or contactpieces connected with said circuit and between which the circuit is closed by the mercury in said bent tube when acted upon by a change of pressure in the gas-supply pipe, a valve in said gas-supply pipe, a motor for closing said valve, and having an electromagnet included in said circuit for controlling the valve-operating motor, and means for preventing momentary fluctuations of pressure in said gas-supply pipe from closing said circuit, substantially as specified.

4c. The combination with a furnace or gasburning device and its gas-supply pipe of an electric circuit, a bent tube containing mercury communicating at one end with the gas supply pipe, electric terminals or contactpieces connected with said circuit and between which the circuit is closed by the mercury in said bent tube when acted upon by a change of pressure in the gas-supply pipe, a valve in said gas-supply pipe, a motor for closing said valve, and having an electromagnet included in said circuit for controlling the valve-operating motor, and a pressure equalizing or regulating reservoir or vessel inserted between said bent tube and the gas-supply pipe, substantially as specified.

5. The combination with a furnace or gasburning device and its supply-pipe, of an electric circuit, an alarm device included in the circuit, a bent tube containing mercury communicating at one end with the gas-supply pipe, electric terminals or contact-pieces connected with said circuit and between which the circuit is closed by the mercury in said bent tube when acted upon by a change of pressure in the gas-supply pipe, a pressure regulator or equalizing reservoir or vessel inserted between said gas-supply pipe and said bent tube, the free end of said bent tube having a small aperture to aid in steadying the movement of the mercury under fluctuations of pressure in the gas-supply pipe, substantially as specified.

6. The combination with a gas-supply pipe of an electric circuit, a bent tube or two-limbed vessel communicating with the gas-supply pipe and containing mercury, electric terminals or contact-pieces extending into each of the two limbs of the vessel, the terminals of the two limbs being at different levels for closing the electric circuit by a rise or fall of pressure in the gas-pipe, a valve in said gassupply pipe, and an electromagnet included in said circuit for automatically operating said valve, and means for preventing momentary fluctuations of pressure in said gas-supply pipe from closing said circuit, substantially as specified.

FRANCIS S. BAKER.

Witnesses H. M. MUNDAY, S. E. CURTIS. 

